There were two recent announcements relating to the installation of battery and electrolyzer technologies that broke world records:

1. Proton Onsite / Nel ASA just announced a contract to supply a PEM-electrolyzer based H2 generation and fueling station that will supply up to 900 kg per day of H2 that will be used for fuel in H2 fuel cell buses in the Palm Springs area of California. The size of this combined electrolyzer / fueling station makes it the largest such station in the world. For perspective, 1 kg of H2 is roughly equivalent to 1 gallon of gasoline, and an average convenience store gas station in the U.S. sells about 4,000 gallons of gasoline per day. So, it will be desirable to make these systems even bigger in the future. You can read more about the Nel ASA fueling station here.

2. Tesla is half way finished building a Li-ion battery system that will be installed in Southern Australia. Once installed, this system will be rated at 100 MW with 129 MWh of capacity, making it the largest grid-tied battery system in the world. For perspective, a typical coal-fired power plant produces around 1000 MW of electricity. You can read more about the Tesla installation in Australia here.

Both California and Australia have been aggressive installing renewable wind and solar, which has resulted in large price fluctuations in both locations, leading at times in negative electricity prices. Using these free or low-cost electrons to to produce fuels or charge up a battery until electricity prices return to normal represent a huge opportunity for these energy storage technologies to grow.

It’s no secret that there will be significant challenges to achieving a clean energy future where a large percentage of society’s energy comes from renewable resources such as solar and wind. Many of these challenges relate to the fact that solar and wind are variable and sometimes intermittent generators– they only produce electricity when the sun is shining and the wind is blowing. Thus, the amount of electricity supplied by these resources is often out of sync with the demand for electricity, an issue that gets worse as solar and wind achieves a larger percentage of a region’s generating capacity. In order to deal with the imbalance with supply and demand, a combination of three actions are often taken:

The price of electricity decreased. Sometimes, electricity prices can even go negative, with a state like CA having excess electricity paying states like Arizona to take the extra electricity off their grid (see article below).

Conventional power plants, such as natural gas plants, are turned off/on to help balance demand and supply.

Excess electricity from solar and/or wind is curtailed, meaning the connection between the solar panel or wind turbine and the grid is cut, and the electricity is wasted. (free electricity!).

In California, where almost 14% of its electricity was obtained from solar in 2016, this grid balancing act is already becoming extremely challenging, as discussed in a recent LA Times article that provides a lot of useful stats and discussion:

In China, which is the world leader in solar panel production and increasingly installing large amounts of solar power plants itself, the imbalance between electricity supply and demand is become especially acute in provinces where transmission of electricity to the large population centers is highly inadequate. According to the article below, curtailment rates of solar-generated electricity are often 30% or higher!:

While improvements to the grid (e.g. smart grid technologies) and demand-side management can go a long way to help alleviate some of the issues involved with balancing electricity supply and demand, there is a limit to how much they can help—especially in a future where solar and wind generate 50% or more of a region’s electricity. In this case, many studies agree that low-cost and scalable energy storage technologies are crucially important. Batteries are one option, and have the benefit of high round trip efficiencies, but electrolyzer technologies that convert electricity into storable chemical fuels are another option. Electricity-to-fuel technologies such as the ones we work on in our lab also represent a huge opportunity because fuels can be used for many energy applications and sectors that are not currently very reliant on electricity. The flexibility and storability of fuels thus make them highly attractive 1.) for their ability to utilize low-cost or free electricity, and 2.) their ability to impact many different energy use sectors (transportation, industrial/chemical, agriculture, commercial) that are predominantly reliant on fossil-fuels at this time.

^credit: the term “The grid’s great balancing act” has been often used by Prof. Cory Budischak at Delaware Technical Community College. A more detailed analysis of a future scenario in which 99.9% of the electricity is provided by solar and wind can be found in a paper that he published a few years ago in J. Power Sources:

There were a couple of recent articles on the growing hydrogen fuel cell vehicle (HFCV) market:

Japan is investing heavily in it’s hydrogen infrastructure. With 80 H2 refueling stations already installed, Japan plans to increase that number to 160 stations supporting 40,000 HFCVs by 2020 when it will host the summer Olympics: https://www.eenews.net/stories/1060054777

In all future hydrogen markets, infrastructure can be a limiting factor because it can be very expensive to build new stations, piping networks, and H2 generation plants to support HFCVs. In a renewable energy future where H2 is produced by water electrolysis driven by energy from wind and solar, a challenge is building this infrastructure that links remote generation sites with lots of solar and wind to densely populated areas where most of the demand will be. In Australia, where there is ample space, sunlight, and wind, there has been discussion of becoming an “hydrogen exporter”, where domestically generated H2 will be shipped as liquid Hydrogen to various locations around the world in H2 tanker ships like the one shown in the rendering below: https://www.theguardian.com/sustainable-business/2017/may/19/how-australia-can-use-hydrogen-to-export-its-solar-power-around-the-world

Artist’s rendition of a tanker that will ship liquid H2 from Australia to Japan as a part of a deal between those two countries that will begin a pilot project in 2020. Image source is the above cited article in the Guardian.

In a preview of a soon-to-be released annual report from the Solar Energy Industries Association (SEIA) and the GTM research, it has been reported that the electricity generating capacity of solar photovoltaic (PV) installations added to the US electrical grid in 2016 was higher than any other type of electricity generating technology. 39% of all new electricity capacity, equivalent to around 14.6 GW, was added in 2016, a 95% increase from 2015. Together, new solar and wind installations comprised 65% of all new electricity generating capacity in the US, reflecting the fact that the costs of solar PV installations have been cost competitive with traditional sources across much of the US.

As the price of electricity from solar PV continues to drop, this creates a huge opportunity to use electrochemical technologies to convert low-cost, carbon-free electricity into storable chemicals and fuels.

This recent article gives a nice summary of the state of H2 fuel cell vehicles in the U.S. and around the world with a focus on describing plans by a company out of Utah (Nikola) to develop a nation-wide H2 refueling network for hybrid H2/electric tractor trailers or semis:

You can see a map of the approximate locations of the planned fueling stations here. “Big rigs” are an exciting opportunity for H2 fuel cells because their larger size (fuel tanks) can be leveraged to give them a long range (distance traveled between fueling), and unlike an average private vehicle, it’s more common for a truck to a few well-defined routes. Thus, an early fleet of trucks can get by on fewer fueling stations. Importantly, an analyst at the Union of Concerned Scientists notes in this article that although big rigs only make up 7-10% of the vehicles on the road, they consume 25% of the fuel.

Although the H2 refueling network in the US is currently confined to California, the article above reports that a network of stations will soon be installed in the Northeast, and points out that extensive systems are in place or being built in other countries in the world like Denmark, Japan, and Germany.

The cover story for the most recent issue of Chemical and Engineering News (c&en) wason solar fuels (aka artificial photosynthesis systems), and includes a nice overview of approaches that researchers are taking in this field: (the story starts on pg. 32):

India has some very ambitious targets set for deployment of solar technology for 2022 and 2030. At the same time, it is currently one of the biggest coal users in the world. Thus, India has huge potential to reduce its (projected) emissions, and it will be interesting to watch how these dynamics play out in the coming years.:

Here is a recent viewpoint article published in ACS Energy Letters discussing the merits of using solar energy (or solar-derived electricity) to 1.) split water for H2 production, or 2.) reduce CO2 into liquid hydrocarbon fuels:

There is a lot of active research ongoing for both of these pathways, so this is an important discussion to be having.

The article nicely articulates the reasons for not performing CO2 reduction from CO2 captured from coal fired power plants. However, there are other sources of CO2 as well, such as cement plants, or capturing CO2 directly from air (so-called negative emissions) as discussed in this article:

We commonly use 3D printing in our lab for making (photo)electrochemical cells and reactors, and electrodeposition for depositing electrocatalytic materials.

Bridging both of these areas is a a recent paper in Energy & Environmental Science (EES) where researchers electroplated Nickel onto 3D printed PLA flow field plates to be used in polymer electrolyte membrane (PEM) electrolyzers: